A number of dangerous and painful disabilities are caused by the excessive resorption of bone. For example, rheumatoid arthritis and periodontitis (both associated with erosive joint disease), osteoporosis, and the failure of prostheses to remain tightly bonded to the underlying bone are all characterized by the excessive resorption of existing bone. Medical research has studied such conditions for some time, but problems have not yet been resolved and treatment methods remain only partially satisfactory.
The mechanism of bone resorption is still the subject of research and speculation. It is known that a class of cells called osteoclasts have the function of resorbing bone, in balance with the formation of new bone by the osteoblasts. Bone loss occurs when the osteoclasts become more active than normal, compared with the osteoblasts. The mechanism by which the functions of bone formation and resorption are balanced, and, accordingly, the mechanism by which unbalance occurs with resulting excessive resorption of bone, continue to be discussed and studied. It has recently been shown that osteoclasts in cell culture can be stimulated by hydrogen peroxide, a member of the class of reactive oxygen species. Bax et el., Stimulation of Osteoclastic Bone Resolution by Hydrogen Peroxide, BBRC, 183, 1153-58 (1992).
There is at present no generally applicable treatment for excessive bone resorption. Estrogens are administered to post-menopausal women for the treatment of osteoporosis, as is well known, but the side effects of such treatment are also well known and the method is not generally applicable to other cases of excessive bone resorption. Thus, medical science is in need of a general treatment for excessive bone resorption, and continues to search for it.